Wordpress, Double comment, Error 500 on ISPConfig 3.0.5.4p5 NGINX

Hello, friends! When Im adding the duplicate comment in Wordpress , the server gives the 500 error --- page wp-comments-post.php
Instead of the message "duplicate comment. It seems you already said that!" .
Please help me to fix it.
I would like to see the message "Found a duplicate comment. It seems you already said that!"